Means for the protection of electrical apparatus



May 17, 1932. J. BETHENOD 1,859,125

MEANS FOR THE PROTECTION OF ELECTRICAL APPARATUS Filed Jan. 10. 1930 s 14 f 6 q I 2/ 3/ //vv/v7-oz HTToz/wzys.

Patented May 1 7, 1932 *umrao STATES PATENT OFFICE Application filedJanuary 10,1930, Serial No. 419,954, and in France January 22, 1929.

The present invention relates to improvements in means for theprotection of electrical apparatus, and giving a Warning, when a faultoccurs in their insulation.

It has already been proposed to protect electrical apparatus, surroundedby an oil bath, when a fault occurs in their insulation, by employinggaseous, vapour or other bubbles formed under the influence of the sparkaccompanying the fault, to operate, by means of an appropriate relay,either a currentbreaker for putting the faulty apparatus out of circuitor a suitable warning device.

The present invention has for object a new system of protection based ona totally different principle from that heretofore employed, which hasthe advantages of not only operating more rapidly than the methodsheretofore employed, but also of being capable of application not'onlyto electric machines and other electrical apparatus placed in a liquiddielectric bath, but also to electrically insulated machines andapparatus surrounded by the atmosphere or placed in any gas or in anysolid insulator whatever. Preferably the said machines or apparatus tobe protected are enclosed in an electrically conducting casing(container, casing or any metallic envelope whatever), which is closedor nearly closed.

The new system or apparatus according to the present inventionis basedon the use of the electro-magnetic radiation, produced by the spark, areor discharges, etc., accompanyingthe fault, to influence an aperiodicreceiving system sensitive to this radiation. This receiving system maysubsequently opcrate, through a suitable amplifier, either a warningdevice (optical, acoustic or other device), or a circuit-breakerforputting the machine or apparatus to be protected out of circuit oreffecting lany otliersuitable protecting operation,,etc. v. v

An objectof the invention, therefore is to provide-meansfor theprotection of e ectrical apparatus, whena fault, accompanied v byaspark, are or other discharge, occurs intheir insulation, comprising,in combination, recelvmg means sensitlveto the electromagnetlc radiationcaused by the spark,

are or other discharge accompanying the occurrence of said fault andmeans connected to said receiving means for operating a suitableprotecting device when said radiation occurs.

The radiation or wave-collecting means are in electrical connection withthe receivlng system properly speaking, according to the invention, andthe whole constitutes thus receiving means which are insensitive andinoperative during ordinary conditions of operation of the apparatus,when no spark, etc., occurs but which are adapted to receive and to beoperated by the radiation accompanying the spark, are or discharges etc.caused by the fault. It will be observed thus that the inventionutilizes the high-frequency electromagnetic waves which are produced bythe spark, are, or discharge which accompany the fault in theinsulation, and that these waves, in the preferred form of device, arereceived by a detector, and thereby render operative the operatingcircuit for the protecting device, which is not in operative conditionuntil such waves are received.

According toa further object of the invention, protecting means may alsobe provided for preventing any untimely operatlon of the main protectingor warning devices of the apparatus to beprotected.

Particularly, in order to avoid any untimely operation caused by anexternal radiation, for example, the receiving system may be placed inthe actual conducting envelope surrounding the machine or apparatus tobe protected, which forms a screen against external radiations.Alternatively, only part of the receiving means, comprising the. wavecollectors, may be placed in this envelope and the other apparatus,constituting the said receiving system, placed in a conducting envelopeseparate from the first but electrically connected to its mass. In thiscase, the connecting wires between the two parts of the receiving meansshould themselves preferably be enclosed in a conducting sheathing forpreventing induction.

Further, in order to avoid the functioning of the protecting or warningdevices when the machine or apparatus to be protected is only submittedto phenomena of short duration, appropriate parts of the receivingsystem or subsequent electrical circuits, such as a relay controlled bythe receiving system, may be time delayed in operation so that it onlyoperates when the duration of the radiation exists a certain length oftime.

The receiving system may be of any suitable type. In particular, typessimilar to those used in radio-electric technique may be used, thesereceivers being made aperiodic by the usual means employed for thispurpose rn this art. The sensitiveness of the receivers will thus beconstant, or substantially constant, independent of the frequency anddamping of the radiated waves.

The Wave collector of the receiving system may comprise, for example,coils of conducting wire arranged around the machine or apparatus to beprotected, inside the conducting casing in which the latter is located,and insulated from thewalls thereof, the number and form of the saidcoils varying with the device tobe protected or the protectingarrangements employed.

The detector of the receiving system may be of any known type but, ingeneral, it is preferable to use a coherer.

In order that the invention may be more fully understood, an example ofits application is described hereinafter with reference to theaccompanying drawing, which represents, diagrammatically, an arrangementfor the protection of a transformer operating in a metallic containerfilled with oil.

In accordance with the invention the transformer 1' is surrounded,inside the metallic container. 2, by several coils 3 of conducting wire,constituting a wave collector, which are insulated from the Walls of thecontainer. The ends of this collector are connected, through an opening-formed in the top of the container 2 and a metallic tube 4:, to areceiving apparatus which is located in another casing 5, also of metal.In the example shown, the receiving system comprises a coherer 6,mounted in series with the wave collector, an additional source ofcurrent, such as a battery or accumulator 7, and a relay 8, ofgalvanometric or other equivalent type, which operates a warning device,or circuitbreaker, etc.

Also, in the different applications of the invention, the receivingsystem may be arranged in such a manner that any accident occurring tothe said system may be revealed by a special warning system or may causethe functioning of the relay operating the principal warning device, orcircuit-breaker, etc. of the system.

Finally, in order to avoid the functioning of the protecting or warningdevices when the machine or apparatus to be protected is' only submittedto transitory phenomena of short duration, produced for example by asudden change in potential, a short circuit, or a sudden opening orclosing of the circuitbreaker, etc, without causing any damage to theinsulation, the relay controlled by the receiving system may be arrangedin such a manner that it only operates when the duration of theelectro-magnetic radiation exceeds a ce ain length of time, which maybe, as is the general case, only a relatively short time.

It will be understood that the term receiving system, when used in theclaims hereafter, shall be understood as signifying the receivingcircuit which includes the detector, source of current, etc, and thatthe term receivin means shall be understood as signifying thewave-collector. and the said receiving system jointly, both in theparticular example of the invention described hereinbefore.

I claim 1. Means for protecting electrical app aratus when a faultoccurs in the insulation, comprising in combination an aperiodicreceiving system sensitive to the high-frequency electro-magneticradiation produced by the spark, are or discharge accompanying theoccurrence of said fault, means for influencing said receiving system bysaid radiation, screens for protecting said means and said receivingsystem from external radiations, and means connected to said receivingsystem for operating a suitable protecting device when said radiationoccurs.

2. Means for protecting electrical apparatus when a fault occurs in theinsulation, comprising in combination an aperiodic receiving systemsensitive to the hi gh-frequenc'y electro-magnetic radiation produced bythe spark, are or discharge accompanying the occurrence of said fault,means for influencing said receiving system by said radiation, screensfor protecting said means and said receivingKsystem from externalradiations, and a relay, connected to said receiving system, foroperating a suitable protecting device when said radiation occurs, saidrelay being so arranged as to operate only when the duration of saidelectromagnetic radiation exceeds a predetermined time.

3. Means for protecting electrical apparatus when a faultoccurs in theinsulation, comprising in combination a Wave collector for receiving thehigh-frequency electromagnetic radiation produced by the spark, are ordischarge accompanying the occurrence of said fault, an aperiodicreceiving system connected to said wave collector and. sensitive to saidradiation, metallic screens for shielding said apparatus to be protectedand said receiving means from external radiations, and means connectedto said receiving system for operating a suitable protecting device whensaid radiation occurs.

4. Means for protecting electrical 'apparatus enclosed in a conductingcasing, when a fault occurs in the insulation, comprising in combinationa wave collector, arranged in the vicinity of said apparatus to beprotected and within said conducting casing, adapted to receive thehigh-frequency electromagnetic radiation produced by the spark, arc ordischarge accompanying the occurrence of said fault, an aperiodicreceiving system sensitive to said radiation, in electrical connectionwith said wave collector, metallic screens for shielding said receivingsystem from external radiations, and means connected to said receivingsystem for operating a suitable protecting device when said radiationoccurs.

5. Means for protecting electrical apparatus enclosed in a conductingcasing, when a fault occurs in the insulation, comprising in combinationa wave collector. Which is arranged within said conducting casing in thevicinity of said apparatus to 'be protected andis adapted to receive thehigh-frequency .electromagnetic radiation produced by the spark, are ordischarge accompanying the occurrence of said fault, an aperiodicreceiving system sensitive to said radiation, an electrical connectionbetween said wave collector and said receiving system, a separateconducting casing for said receiving system whereby the system isscreened from external radiations, and means connected to said receivingsystem for operating a suitable protecting device when. said radiationoccurs.

6. Means for protecting electrical apparatus in accordance with claim 5,wherein the connecting wires between the wave collector and thereceiving system are enclosed in a metallic sheathing to preventinduction.

7. Means for protecting electrical apparatus in accordance with claim 3,wherein said receiving system operates the protecting device through arelay so arranged as to operate only when the duration of the electromagnetic radiation caused by the occurrence of said fault exceeds apredetermined time.

8. Means for protecting electrical apparatus in accordance with claim 3,wherein said receiving system comprises in combination a cohererconnected to said wave collector and a relay of the galvanometric typeconnected to said coherer, and adapted to operate said protectingdevice.

9. In means for the protection of electrical apparatus, when a faultoccurs in the insulation, the combination of a wave-collector forreceiving high-frequency electromagnetic waves produced by the spark,are, or discharge accompanying said fault, means for operating aprotecting device for said apparatus when such fault occurs, and meanspositioned to receive said'waves from said collector and renderedoperative'thereby to operate said protective-device-operating means.

A 10. In means for the protection of electrical apparatus, when a faultoccurs in the insulation, the combination of a wave-collector coil woundcompletely around the apparatus to be protected and adapted to receivehigh-frequency electromagnetic waves produced by the spark, are, ordischarge accompanying trical apparatus, when a faultoccurs in theinsulation, the combination of a wave-collector for receivinghigh-frequency electromag-.'

netic waves produced by the spark, are, or discharge accompanying saidfault, a receiving system connected to said wave-collector andcontaining a source of currentand a de-' tector, and means for operatinga protecting device for said apparatus when said fault occurs,'connectedto said circuit and operated by said source when such high frequencywaves are received by said circuit.

12. Means for the protection of electrical apparatus, when a faultoccurs in the insulation, comprising, in combination, a wave-collectorfor receiving the high-frequency electromagnetic radiation produced bythe spark, arc, or discharge accompanying the occurrence of said fault,said wave collector comg spark, are or discharge accompanying a fault insaid apparatus, said means comprising a wave collector coil woundcompletely around the apparatus to be protected, and a receivmg circuitconnected to said coil means connected to said. receiving means foroperating a suitable protecting device for said apparatus when saidradiation occurs, and means for preventing unintended operation of saidprotecting device.

14. Means for the protection of electrical.

apparatus comprising, in combination, an aperiodic receiving systemsensitive to the high-frequency electromagnetic radiation produced bythe spark, arc or discharge accompanying a fault in said apparatus,means for influencing said receiving system when said radiation occurs,means connected to said receiving system for operating asuitableprotecting device, and means. forpreventing unintended operation of saidprotecting devlce.

15. Means for the protection of electrical apparatus comprising, incombination, an aperiodic receiving system sensitive to thehigh-frequency electromagnetic radiation 5 produced by the spark, are ordischarge accompanying a fault in said apparatus, means for influencingsaid receiving system when said radiation occurs, protecting means'forpreventing operation of said receiving systorn by radiations other thanthat caused by said fault, and means connected to said receiving systemfor operating a suitable protecting device for said apparatus when saidI radiation occurs.

16. Means for the protection of electrical apparatus comprising, incombination, an aperiodic receiving system sensitive to thehigh-frequency electromagnetic radiation produced by the spark, arc ordischarge accompanying a fault in said apparatus, means for influencingsaid receiving system by said radiation. protecting means for preventingoperation of said receiving system by radiations other than that causedby said fault,

and means connected to said receiving system for operating a suitableprotecting device for said apparatus, said means comprising a relayoperatin through said receiving system when said radiation occurs,

0 17. Means for protecting electrical apparatus enclosed in a conductingcasing, when a fault occurs in the insulation of' said apparatus,comprising, in combination, a wavecollector for receiving thehigh-frequency electromagnetic radiation produced by the spark, arc ordischarge accompanying the occurrence of said fault, comprising coils ofconducting wire arranged completely around the apparatus to be protectedand electrical- 40 ly insulated from said casing, a receiving systemsensitive to said radiation, in electrical/connection with saidwave-collector, and means connected to said receiving system foroperating a protecting device for said apparatus whensaid radiationoccurs.

18. Means for protecting electrical apparatus when a fault occurs in theinsulation thereof, comprising, in combination, a wavecollector arrangedin the vicinityof the apparatus to be protected and adapted to receivethe high-frequency electromagnetic radiation produced by the spark, arcor discharge accompanying the occurrence of said fault, a receivingsystem sensitive to. said radiation,

in electrical connection with said wave-collector, and means connectedto said receiving system for operating a protecting device for saidapparatus when said radiation occurs, said system comprising a coherer,arelay adapted to operate the protecting device, a source of current,and connections between the same.

In testimony whereof I have hereunto affixed my signature.

JOSEPH 'BETHENOD.

CERTIFICATE OF CORRECTION.

Patent No. 1,ss,12s. May 17, 1932.

JOSEPH BETHENOD.

It is hereby certified that error appears in the printed specificationof the above numbered patent requiring correction as follows: Page 3,strike out lines 47 to 53, inclusive, comprising claim 8, ,and insertthe following as claim 8:-

8. Means for protectingv electrical apparatus in accordance with claim3,:wher'ein said protecting device for said apparatus is operatedthrough a relay of the galvanometric type connected to said wavecollector through a coherer.

and'that the said Letters Patent should be read with this correctiontherein that the same may conform to the record of the case in thePatent Office.

Signed and sealed this 12th day of July, A. D. 1932.

. M. J. Moore, (Seal) Acting Commissioner of Patents.

